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| author | James Morse <james.morse@arm.com> | 2024-08-19 14:15:53 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-18 08:24:58 +0200 |
| commit | ec5bca57afc6bef581f800f8f9496f2ae1633271 (patch) | |
| tree | c1ae220f360f6d09b90266aea2ccef16b447c262 /arch | |
| parent | 2a3915e86187ea8a48e7f899ec3fb000f8159fb6 (diff) | |
| download | linux-ec5bca57afc6bef581f800f8f9496f2ae1633271.tar.gz linux-ec5bca57afc6bef581f800f8f9496f2ae1633271.tar.bz2 linux-ec5bca57afc6bef581f800f8f9496f2ae1633271.zip | |
arm64: proton-pack: Expose whether the platform is mitigated by firmware
commit e7956c92f396a44eeeb6eaf7a5b5e1ad24db6748 upstream.
is_spectre_bhb_fw_affected() allows the caller to determine if the CPU
is known to need a firmware mitigation. CPUs are either on the list
of CPUs we know about, or firmware has been queried and reported that
the platform is affected - and mitigated by firmware.
This helper is not useful to determine if the platform is mitigated
by firmware. A CPU could be on the know list, but the firmware may
not be implemented. Its affected but not mitigated.
spectre_bhb_enable_mitigation() handles this distinction by checking
the firmware state before enabling the mitigation.
Add a helper to expose this state. This will be used by the BPF JIT
to determine if calling firmware for a mitigation is necessary and
supported.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/spectre.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/proton-pack.c | 5 |
2 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h index f1524cdeacf1..78fb720987fb 100644 --- a/arch/arm64/include/asm/spectre.h +++ b/arch/arm64/include/asm/spectre.h @@ -97,6 +97,7 @@ enum mitigation_state arm64_get_meltdown_state(void); enum mitigation_state arm64_get_spectre_bhb_state(void); bool is_spectre_bhb_affected(const struct arm64_cpu_capabilities *entry, int scope); +bool is_spectre_bhb_fw_mitigated(void); void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *__unused); bool try_emulate_el1_ssbs(struct pt_regs *regs, u32 instr); diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c index 30e79f111b35..c5e0c092721e 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -1093,6 +1093,11 @@ void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *entry) update_mitigation_state(&spectre_bhb_state, state); } +bool is_spectre_bhb_fw_mitigated(void) +{ + return test_bit(BHB_FW, &system_bhb_mitigations); +} + /* Patched to NOP when enabled */ void noinstr spectre_bhb_patch_loop_mitigation_enable(struct alt_instr *alt, __le32 *origptr, |